Cartridge adapters for high-powered firearms



April 8, 1969 G. T. KOEHLER CARTRIDGE ADAPTER FOR HIGH-POWERED FIREARMS INVENTOR. Goep 0m 7? K0014 1? BY 3,437,040 CARTRIDGE ADAPTERS FOR HIGH- POWERED FIREARMS Gordon T. Koehler, 421 Acorn Drive, Dayton, Ohio 45419 Filed Feb. 23, 1967, Ser. No. 618,125 Int. Cl. F42b 13/00 U.S. Cl. 102-41 2 Claims ABSTRACT OF THE DISCLOSURE An adapter cartridge shaped to fit the firing chamber of a high-powered firearm and having a central bore there- Ithrough which is enlarged at its upper end to receive a projectile, and restricted beneath the projectile to form a chamber to receive a low-powered cartridge, from which the bullet has been removed. A. metering plug mounted in the chamber and extending within the case of the low-powered cartridge and adjustable in relation to the powder charge therein to control the burning of said charge. Openings in the sidewall of the adapter give access to the chamber for the insertion and removal of the lowpowered cartridge. A plunger freely supported in the central bore beneath the chamber carries a firing pin which forms an operating connection between the lowpowered cartridge and the firing mechanism of the firearm.

This invention relates to ammunition for small firearms and is particularly directed to means for adapting a low-powered small caliber cartridge for use in comparatively high-powered large caliber firearm, to provide an economical load or charge suitable for use in indoor traget practice, for example, and for hunting small game.

A general object of the present invention is to provide means for using a reduced or low-powered charge or load in high-powered firearms.

Another object is the provision of an adapter cartridge for use in high-powered firearms, said adapter arranged to accept an inexpensive low-powered cartridge and a suitable lightweight bullet for the economical use of said firearm for accurate short range firing, such as, indoor target practice and/or the hunting of small game.

With these and other incidental objects in view the invention includes certain novel features of construction and combinations of parts, a preferred form or embodiment of which is hereinafter described with reference to the drawings which accompany and form a part of this specification.

In the drawings:

FIG. 1 is an elevation of the adapter cartridge, partially sectioned along line 1--1 (FIG. 3) showing the manner in which the low-powered cartridge is inserted in said adapter, the pressure controlling metering plug which is adjustably mounted in the upper end of said adapter and adjustable in relation to the low-powered cartridge, and also showing the firing plunger which forms a firing connection between the usual firing mechanism of the high-powered firearm and the low-powered cartridge.

FIG. 2 is a right angle projection of the adapter shown in FIG. 1, and is partially sectioned along lines 2-2 (FIG. 4) to better show the internal construction of said adapter.

FIGS. 3 and 4 are, respectively, right angle projections of the upper ends of the adapter shown in FIGS/1 and 2.

FIG. 5 is a horizontal elevation of the pressure con- States Patent 0 2 trolling metering plug which forms an important part of the adapter shown in FIGS. 1 and 2.

FIGS. 6 and 7 are, respectively, right angle projections of the left-hand and right-hand ends of the metering plug shown in FIG. 5.

FIG. 8 is a sectional view in elevation of the firing plunger which forms an active firing connection between the low-powered cartridge used in the adapter, and the regular firing mechanism of the high-powered firearm, in which said adapter is being used.

DESCRIPTION It is desirable and essential that owners of highpowered long range hunting firearms or rifles become thoroughly familiar with said firearms by repeated firing before using them in the hunting of large game. There is no satisfactory way for said owners to gain this information or familiarity in restricted or confined areas as it i impractical, dangerous and unlawful to fire a high-powered firearm in this manner. Along with the inconvenience of finding a suitable area in which to fire the high-powered firearm is the expense involved in using high-powered hunting ammunition in sufiicient quantities to become thoroughly familiar with the use of said arm.

To overcome all of the above inconveniences and expense, applicant has devised an auxiliary adapter which fits the chamber of the high-powered firearm and accepts a low-powered inexpensive cartridge, such as a .22 caliber rimfire cartridge, and a suitable inexpensive bullet to satisfactorily adapt the arm for safe and accurate short range firing, such as indoor target practice and the hunting of small game in restricted or confined areas.

Referring to the figures of the drawings in which like reference numerals refer to like parts, the adapter cartridge comprises a case 10, the external contour and dirnensions of which are exactly the same as the highpowered cartridge that it is being used to repalce, so as to properly fit the chamber of the firearm in which it is to be used. The case 10 is made of any suitable material, such as bronze or aluminum alloy, and has a central bore 11 which freely supports a firing plunger 12 having near its upper end a stop pin 13 which extends through either of two similar and diametrically opposed openings 14 in the case 10, said openings serving to provide ample room for inserting a low-powered cartridge 15, in this case a .22 caliber rimfire cartridge, in the case 10. The stop pin 13 coacting with the opening 14, prevents the firing plunger 12 from falling out of the central bore 11 in the adapter 10, and is preferably made of some yieldable material, such as rubber of the proper resilience, so that said pin may be depressed within the opening 14, in case it is necessary or desirable to remove said plunger from the case 10.

The .22 rimfire cartridge 15 (FIGS. 1 and 2) is a standard cartridge in every respect and available wherever ammunition is for sale.

A reduced portion 16 of the central bore 11 is of proper diameter to form a chamber to freely receive the lowpowered cartridge 15, when it is inserted therein, as shown in FIGS. 1 and 2. With the plunger 12 in its lower position, as determined by the pin 13 engaging the lower edge of the opening 14, the cartridge 15 may be inserted through either of the openings 14 by use of the thumb and forefinger and slid upward into the reduced bore 16, after which the plunger is moved upwardly into firing position, as shown here. It will be noted by observing 3 FIGS. 1 and 2 that, the usual bullet is removed from the cartridge 15 prior to its insertion in the bore 16, as explained above.

A metering plug 17 is adjustably mounted in the upper end of the adapter and coacts with the cartridge to control the pressure generated by the powder in said cartridge upon firing, to greatly imporve the accuracy of said adapter, as will be explained presently. The lower end of the metering plug 17 (FIG. 1) is of proper diameter to snugly engage the interior of the cartridge 15 while the uper end of said plug is threaded to engage similar threads in the upper end of the reduced bore 16 so that said plug may be adjusted in relation to the cartridge 15. The plug 17 has a central metering bore 18 of suitable diameter to properly control the pressure between the cartridge 15 and a bullet 19, which may be produced by properly frorning or swaging a large size buckshot, so as to be a push fit in a counterbore 20* in the upper end of the adapter 10, said counterbore being in axial alinement with the reduced bore 16 and the central bore 11. The lower end of the metering bore 18 in the plug 17 is formed to receive a suitable Allen wrench for adjusting said plug in relation to the cartridge 15. If desired, the receptacle for the Allen wrench may be formed in the upper end of the bore 18 instead of in the lower end, as shown here.

By referring to FIGS. 1 and 8, it will be seen that a firing pin 21 for the cartridge 15, formed of a suitable material such as tempered steel, is secured by a press fit in a bore in the upper end of the plunger 12, so as to position said firing pin in alinement with the rim of the cartridge 15, as shown here. A replaceable contact or striking plug 22 is secured by a push fit in a central counterbore 23 in the lower end of the plunger 12 and forms a firing connection between said plunger and a firing pin 24 of the high-powered firearm (not shown) in which the adapter 10 is being used. The upper end of the counterbore 23 is threaded to receive a screw-plug 25 used to adjust the striking plug 22 in relation to the tip of the firing pin 24, to maintain proper firing relationship between the plunger 12 and said firing pin 24, when said plug 22 is severely indented or deformed by the firing pin 24 upon repeated use thereof. The screw-plug 25 is operated by means of a suitable Allen wrench which is inserted through a central bore 26 in the plunger 12 and into a suitable receptacle in the upper end of said plug In FIG. 1 the metering plug 17 is adjusted in proper relationship to the powder charge of a .22 long rifle cartridge, and in FIG. 2 said plug 17 is shown adjusted in proper relationship to the powder charge of a .22 short cartridge.

With the metering plug 17 adjusted in proper relationship to the type of cartridge being used, the bullet 19 is pushed into the counterbore 20 in the upper end of the adapter case 10 and seated against the shoulder formed by said counterbore 20 and the reduced bore 16, as shown in FIGS. 1 and 2. Next, with the plunger 12 in its lower position, the cartridge 15 is inserted in the chamber formed by the reduced bore 16, by using the thumb and forefinger as previously mentioned, and then pushed upwardly until properly seated in said reduced bore 16, after which the plunger 12 is moved upwardly until the firing pin 21 contacts the rim of the cartridge 15, as shown here.

After the adapter has been prepared, as explained above, it may be inserted in the chamber of a suitable firearm, whereupon operation of the firing mechanism of said firearm causes the firing pin 24 (FIG. 1) thereof to drive the plunger 12 upwardly to cause the firing pin 21 to strike the rim of the .22 cartridge 15 to fire said cartridge, and the bore 18 in the metering plug 17 controls the burning of the powder in said cartridge 15 to drive the bullet 19 through the bore of the firearm at a 1 controlled, uniform and sustained rate of speed so as to maintain maximum accuracy of the flight of said bullet for use in indoor target practice and/or for small game hunting.

If desired, several of the adapters 10 may be loaded in the magazine of a repeating high-powered firearm and fed from said magazine into the chamber of said firearm in the same manner as regular high-powered ammunition.

After firing, the adapter 10 may be ejected from the chamber of the firearm and the fired cartridge 15 removed from the bore 16 by grasping the flanged end or rim of the said cartridge 15 with the thumb and forefinger and pulling it downwardly out of said bore 16. The adapter 10 may be prepared and used, in the manner explained above, repeatedly, without damage to it or to the firearm in which it is being used.

While the form of mechanism herein shown and de scribed is admirably adapted to fulfill the objects primarily stated, it is to be understood that it is not intended to confine the invention to the form or embodiment herein disclosed for it is susceptible of embodiment in various other forms all coming within the scope and spirit of this invention.

What is claimed is:

1. In a device for adapting a low-powered cartridge for use in a high-powered firearm, the combination of a cartridge-shaped casing of proper outside dimensions and contour to fit the chamber of the firearm, said casing having a central bore of suitable diameter to receive in its upper end a projectile of suitable size and weight, said bore having a restricted prtion near its upper end and beneath the location of the projectile to form a chamber to receive the cartridge, when the bullet is removed therefrom; diametrically opposed openings in the casing providing access to the central bore and the chamber to permit the finger-insertion and removal of the cartridge in and from said chamber; means mounted in the central bore of the casing between the cartrdige and the firing mechanism of the firearm and fonming an operating connection therebetween whereby operation of said firing mechanism ignites the powder-charge in said cartridge; and a metering plug adjustably mounted in the central bore of the casing between the projectile and the cartridge and adjustable to extend within the case of said cartridge in proper coacting relationship with the powdercharge therein, said plug having a metering aperture of proper dimension to control the duration of the burning of the ignited powder-charge to obtain uniformly accurate flight characteristics of the projectile.

2. In a device for adapting a low-powered cartridge for use in a high powered firearm, the combination of a cartridge-shaped casing of proper outside dimensions and contour to fit the chamber of the firearm, said casing having a central bore of proper diameter to receive in its upper end a projectile of suitable size and weight, said bore having a restricted portion near its upper end and beneath the location of the projectile to form a chamber to receive the low-powered cartridge, when the bullet is removed therefrom; diametrically opposed openings in the casing providing access to the central bore and the chamber to permit the finger-insertion and removal of the cartridge in and from said chamber; a plunger freely supported in the central bore so that its lower end is in coacting relationship with the firing mechanism of the firearm; yieldable stop means in the plunger and coatcing with one of the openings to limit the free movement of said plunger in the central bore, said stop means being compressible to permit intentional removal of said plunger from said central bore; a firing pin mounted in the upper end of the plunger is coacting relationship with the rim of the low-powered cartridge; adjustable striking means mounted in the plunger in coacting relationship with the firing mechanism of the firearm and adjustable in relation thereto to compensate for any variation between said 5 6 striking means and said firing mechanism caused by wear the ignited powder-charge to obtain accurate and uniform or impact, to insure that operation of said firing mechaflight Chara teristics of the projectilenism will invariably discharge the low-powered cartridge;

References Cited and a metering plug ad ustably mounted 111 the central bore of the casing between the projectile and the low- 5 UNITED STATES PATENTS powered cartridge and adjustable to extend within S id 1,0 5 5/1913 Chadwick 102-41 cartridge in proper relationship to the powder-charge 2,321,737 6/ 1943 Engel 1 therein when said cartridge is properl inserted i th 2,098,068 11/1937 5 1O241 chamber, said metering plug having a metering aperture 2812713 11/1957 Fltzslmmons 1O2 41 of suitable dimension to control the pressure created by 10 ROBERT F. STAHL, Primary Examiner. 

